Hockey Stick Goes to Washington - The Hockey Stick and the Climate Wars - page 82

century.” While I recognized the importance of refuting the Soon and Baliunas study—and of
defending our own and other independent confirmatory studies indicating the anomalous nature of
recent warming—I also sought to emphasize the key larger points: that scientific understanding comes
through expert assessments and the consensus of collective independent studies, and that the balance
of scientific evidence clearly points to the reality of human-caused climate change.
The hearing, as one might have expected, emphasized theater over substance and myth over fact.
I spent much of my testimony refuting the various claims Soon and Legates made. I explained, for
example, to Senator Allard why so-called CO 2 fertilization (the hypothesis that plants will take up
greater amounts CO 2 in a warmer world, therefore mitigating its buildup in the atmosphere) was not
the panacea that Legates and Soon had argued it was, 35 noting that any increases in carbon uptake tend
to saturate quickly with further warming. When Legates and Soon asserted that satellite data
contradict surface observations of warming, Jeffords knew I was anxious to rebut this standard of
climate change denial, and he gave me the opportunity to point out that the claim had “pretty much
been debunked in the peer-reviewed literature.”
Inhofe claimed at one point that my testimony had somehow impugned the integrity of the two
other witnesses. I took issue with the assertion and noted that I had simply questioned “their
qualifications to state the conclusions that they have stated.” There were a number of other testy
exchanges. In refuting a Legates claim that models are unable to reproduce modern observations, I
pointed out that they, in fact, “track the actual instrumental warming and the slight cooling in the
northern hemisphere [from the 1950s to the 1970s].” Inhofe cut me off, however, directing me to
comment instead on his projections of the cost of mitigating climate change (should it exist), based on
estimates by one particular group. 36 (His projections were very high, and of course with no
consideration of the costs of not reducing CO 2 emissions.) “I am not a specialist in public policy and
I do not believe it would be useful for me to testify on that,” I responded. While the hearing was
ostensibly about climate science, Inhofe and his allies often appeared to want to talk about anything
but that.
Partway through the hearing, Senator Hilary Clinton arrived. Her opening statement reflected a
nuanced view of the issues. She expressed concern for the balance decision makers must make
between quality of life in the here-and-now and the sustainability of our future. But she left no
uncertainty about where she felt the burden of proof lay on climate change: “I just want to believe that
I am making a contribution to ensuring that the quality of life for future generations is not
demonstrably diminished. I would feel terrible if I participated, either as a willing actor or a
bystander, in this potential undermining of our Earth's sustainability.”
Clinton then turned to me, “So, Dr. Mann, let me ask you, what was the Earth's climate like the
last time that there was atmospheric concentration of carbon dioxide at today's levels of 370 parts per
million?” I took advantage of the question to provide what I felt was much-needed context and an
appreciation for the profound influence human activity was now having on our climate. “We have to
go back to the time of dinosaurs probably to find CO 2 levels that we know were significantly higher
than CO 2 levels today,” I said and went on to articulate what I felt to be the key point: that it is not the
absolute levels of greenhouse gases, but the rate at which we are increasing them, that is the worry.
Past changes had taken place over tens of millions of years, while the changes taking place today
were occurring “on timescales of decades.” It was these rare, brief opportunities potentially to